If you have not already done so I would encourage you to have an open and honest discussion to find out the root cause of the problem. If you show a sincere desire to understand and correct the issue you will probably get a positive response from the Soldier. You do not have to do this but it shows you care.
There are several methods to correct a negative attitude. In this case I might suggest the following: Have the Soldier go to the post library or public library and check out a book called Over the Top by Zig Ziglar.
Bottom line: the Soldier needs to change how they view themselves and their environment. I know it sounds touchy-feely but it is a valuable lesson if the Soldier wants to listen and learn. Require the Soldier to read Chapter 5: “Changing the Picture.” It is about is about 20 pages long. The chapter is about attitude and how to look at things differently. I would encourage you to read the chapter first so you understand the content. It is very effective and I have used it before.
Have the Soldier read the chapter and complete a 500-1000 word essay on attitude or require the Soldier to have a discussion with you on the Chapter. Have him briefly summarize what he read, how it applies to his particular situation, and then how he will implement what he learned. The goal here is to get the Soldier to understand that Attitude and Tone are significant factors in solving problems and teamwork. To be a good leader you must be a good follower. If you can accomplish this corrective training without a counseling statement it would be better to do it this way. If the Soldier continues to have a bad attitude you can reference this session as corrective training and a verbal counseling in your next formal counseling statement.
If this fails to achieve your goal you could inform him that failing to correct his attitude could lead to separation from service under failure to adapt.